If baking immediately, preheat the oven to 350°. Grease a 10x15 baking pan.
If making homemade enchilada sauce, prepare it and set it aside. (Make enough for 6 cups.) In a medium skillet, brown the ground beef and onion and season to taste with garlic salt, cumin, and chili powder.
Drain excess grease then stir in 1/2 cup of enchilada sauce (or enough for it to be moist but not soupy) and set the meat aside to cool.
Pour 1/4 cup of the enchilada sauce into the bottom of the prepared baking dish.
Spread a spoonful of meat and a couple Tbsp of cheese down the center of a tortilla, tightly roll it up, and place it (seam down) in the pan. Repeat with the rest of the tortillas and filling.
If you are baking these later, cover them with plastic wrap and refrigerate or freeze.
When you're ready to bake them, pour the remaining enchilada sauce over the enchiladas then sprinkle the remaining cheese over the top. *Try to cover as much of the tortillas as possible with the sauce - that will help keep them from drying out.
Bake for 20-30 minutes or until the sauce is bubbly and the cheese is thoroughly melted.